This invention relates to a transducer support assembly and, more particularly, for such a support assembly that is particularly designed for use in a disk drive containing a disk pack for playing or playing/recording information on the disks included in that disk pack.
Disk drives have become common peripheral devices for use with information processors, such as computers, for the storage of relatively large amounts of information. Typically, such disk drives are of the so-called rigid disk type in which one or more disks (referred to as a "disk pack") cooperate with a plurality of transducers, conventionally known as record/playback heads, for the magnetic recording and/or reproduction of digital information. Other disk drives are known as "floppy disk" drives in which digital information is magnetically recorded on and reproduced from one or more flexible disks. It also has been proposed to provide non-magnetic disks for information storage purposes, such as optical disks in which information is optically read from a disk, and capacitive disks in which information recorded on or in the surface of a disk is capacitively picked up therefrom. The aforementioned disk drives are provided as separate units disposed in housings that are separate and apart from the information processing system with which they are used; and, more recently, such disk drives have been physically incorporated into the same overall cabinet that houses the information processing system, such as so-called microcomputers, minicomputers, or the like.
One objective in designing disk drives for use with microcomputers in particular is to minimize the overall physical size of the disk drive while increasing the storage capacity thereof. Storage capacity is improved by recording a greater number of tracks on the surface of each disk and by disposing several disks within the disk drive housing. As the number of such disks (i.e. the number of disks included in the disk pack) increases, the available space and physical tolerances within the disk drive housing are reduced. For example, if two disks are disposed within the housing, four disk surfaces are available for recording/reproducing data. Typically, a transducer, or magnetic head, cooperates with a surface for the purpose of writing information thereon and reading information therefrom. However, because of reduced space within the housing, the transducers which cooperate with the bottom surface of one disk and the facing top surface of the other may potentially interfere.
One type of support assembly that has been proposed for a disk drive of the aforementioned type is described in Volume 26, No. 3A, IBM Technical Disclosure Bulletin, August 1983, pages 1250-1252. In that assembly, the head is supported on a flexible suspension formed of thin sheet metal, and this suspension is, in turn, mounted on a rigid support arm, the latter being positioned on an actuator carriage or other carrier. Each flexible suspension bends to urge the head toward or against the disk. When the disk rotates, the head "rides" on a thin film of air so as to avoid contact with the disk and reduce the risk of damage.
In the just-mentioned transducer assembly, two pairs of heads are mounted on respective flexible suspensions, each pair cooperating with the top and bottom surfaces, respectively, of a single disk. One rigid support arm supports one suspension whose head cooperates with the top surface of a first disk, and another rigid support arm supports another suspension whose head cooperates with the bottom surface of a second disk. A third support arm, disposed between the first and second arms, supports two suspensions, one of which carries a head that cooperates with the bottom surface of the first disk and the other of which carries a head that cooperates with the top surface of the second disk. Thus, the central support arm carries two suspensions, but this central support arm is sufficiently thick that the two suspensions are mounted on the opposite (top and bottom) surfaces of that arm. The separation between these suspensions, defined primarily by the thickness of the support arm, is sufficient to avoid interference between the suspensions during operation or during initial "loading", or assembly, of the suspensions and heads with respect to the disks.
As the size and interior spatial dimensions of disk drives decreases, the thickness of the respective support arms likewise decreases. In a disk drive of the type with which the present invention finds ready application, the support arm is sufficiently thin that if suspensions are mounted on the opposite (top and bottom) surfaces thereof, as in the arrangement described in the aforementioned IBM Technical Disclosure Bulletin, those suspensions would interfere with each other during initial "loading" of the head assembly and possibly during actual operation of the disk drive. Furthermore, it is preferred to provide suspensions that are far simpler to manufacture than the type shown in the aforementioned IBM Technical Disclosure Bulletin; and one type of preferred suspension is shown in U.S. Pat. No. 4,443,824. When suspensions of this preferred type are used in disk drives having limited interior spatial dimensions, the problem of interference therebetween becomes more pronounce.